WASHINGTON (AP) — AirTran and Jet Blue have taken the top spots in a national survey of airline quality.

They were followed by Southwest, Northwest and Frontier airlines. At the bottom of the list was Atlantic Southeast Airlines.

The annual Air Quality Rating survey released Monday found that overall the industry did a poor job last year. There were more lost bags, more bumped passengers, more consumer complaints and fewer on-time flights than in the previous year.

The rate of consumer complaints was up 60 percent. US Airways had the most complaints last year. Southwest had the fewest.

All these problems are making travelers grumpy, the annual survey said.

The past year "was the worst year ever for the U.S. airlines," said Brent Bowen, a study co-author and professor at the University of Nebraska at Omaha's Aviation Institute. "Overall operational performance and quality declined once again to the lowest level that it's ever been."

The industry posted declines last year in every area of the Airline Quality Rating, amid rising fuel prices, safety problems and bankruptcy filings that shut down three carriers last week alone.

The rate of consumer complaints, for example, more than doubled at US Airways and Comair, and rose for 15 of the 16 airlines included in the study. The exception was Mesa Airlines.

On-time arrivals dropped for the fifth straight year, with more than one-quarter of all flights late, according to the survey. The rates of passengers bumped from overbooked flights and bags lost, stolen or damaged also jumped in 2007.

"The trend is bad and it doesn't look like it gets any better," said Dean Headley, an associate professor at Wichita State University and co-author of the study. The survey results mesh with the spate of problems that have beset U.S. carriers, starting with surging fuel costs, Headley said.

ATA, Aloha Airlines and Skybus stopped flying just last week because of financial pressures. Major airlines have slashed jobs and passenger amenities while adding fees for second bags, traveling with pets and booking tickets by phone.

It is not surprising that people responded to higher prices and more frequent delays by complaining more, Headley said.

Six airlines — Frontier, Northwest, SkyWest, Southwest, United and US Airways — showed declines in every area in the survey, although Southwest still had the best on-time arrival mark at 80.1 percent.

The Dallas-based carrier also had the lowest rate of consumer complaints, 0.26 per 100,000 passengers.

Still, the airline has not been immune from problems. It is fighting a record $10.2 million fine from the Federal Aviation Administration for continuing to fly dozens of Boeing 737s that hadn't been inspected for cracks in their fuselages.

American, Delta and United airlines recently canceled flights to perform unscheduled inspections of certain aircraft, and US Airways found problems on some Boeing 757s after a wing part on one of its planes fell off during a flight.

The Airline Quality Rating study, compiled annually since 1991, is based on Transportation Department statistics for airlines that carry at least 1 percent of the passengers who flew domestically last year. The research is sponsored by the Aviation Institute at the University of Nebraska at Omaha and by Wichita State University.

The other airlines in the survey were AirTran, Alaska, American Eagle, Atlantic Southeast, Continental, Jet Blue and Mesa.

Among the study's conclusions:

—The rate of consumer complaints about Mesa dropped by one-third and the airline also showed improvement in its rates of bumping passengers and mishandling bags.

—More than one-third of Atlantic Southeast Airlines flights were late, the worst on-time performance in 2007. The airlines also bumped passengers more often, at a rate of 4.5 per 10,000 passengers.

—JetBlue and AirTran were far ahead of their competitors in avoiding bumping passengers from flights, at 0.02 and 0.15 per 10,000 passengers, respectively.

—AirTran had the best baggage handling rate, at 4.06 mishandled bags per 1,000 passengers.

—American Eagle ranked last in baggage handling with 13.55 mishandled bags per 1,000 passengers.

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On the Net:

Transportation Department: http://www.dot.gov

Study site: http://www.aqr.aero/